Rechargeable battery pack



FIG. 1 is the front perspective view showing my new design;

FIG. 2 is the front view thereof;

FIG. 3 is the left-hand view thereof;

FIG. 4 is the right-hand view thereof;

FIG. 5 is the rear view thereof;

FIG. 6 is the top view thereof; and,

FIG. 7 is the bottom view thereof. 

The ornamental design for a "rechargeable battery pack," as shown and described. 